you will ned an angle grinder, a mig welder, array of hammers or those dolly things the panel beaters have if you feel like gettin picky, some thin sheets of steel or ally.
i used computer cases and scrap bit of galv steel
now, you grind all the rust away
cut sheet metal to approx hole size and rivet or tack weld into place then weld all around the hole, being shit box corolla metal thats been rusted you will prob find it does burn back some even on the lowest setting (i wrote my name thru the metal with my mig in one section when i did mine lol) once thats in place theres a product called "penetrol" that you paint on and it stops the rust and paint sticks well as opposed to fish oil :P
then you grind back your weld, bog and shape, prime and paint
;)